In recent years, with spread of molecular target drug therapy focusing on an antibody drug, quantification of a biological substance on an observation target cell is required in order to design a molecular target drug more effectively. As a method for confirming presence of a biological substance, a tissue analysis method based on combination of a fluorescent substance bonded to a biological substance recognition site and a biological substance corresponding to the biological substance recognition site is known.
For example, Patent Literature 1 describes a method for staining a specific antigen of a tissue section with a plurality of fluorescent substance-containing nanoparticles and generating information on the specific antigen in the section based on a fluorescent signal of the nanoparticles.
According to the method described in Patent Literature 1, a fluorescent signal is observed in a form of dots without being buried in autofluorescence or the like of a tissue by using fluorescent substance-containing nanoparticles of high brightness as a fluorescent labeling material. This makes it easy to measure the number of a biological substance per cell based on a fluorescent signal of nanoparticles.